This invention relates to a disposable pull-on diaper adapted to be secure in rolled up state for disposal after use.
It is well known in the art to provide a disposable pull-on diaper with tape fasteners by which the diaper may be secured in rolled up state for disposal after use. For disposal, the diaper is rolled up in the longitudinal direction starting from the crotch region toward the peripheral edge portion of the waist-opening or vice versa and then the tape fasteners are wound around the outer surface of such rolled up diaper to secure the diaper in this rolled up state. The tape fastener is made of flexible plastic sheet coated on its inner surface with pressure-sensitive adhesive by means of which the tape fastener is anchored on the outer surface of the diaper.
The disposable pull-on diaper provided with such tape fasteners is well known, for example, from Japanese Patent Application Publication Nos. 1998-71172A, 1998-71173A and 1998-85254A.
Use of the tape fasteners to secure the diaper in rolled up state is advantageous in that the handling for disposal is conveniently simplified. However, use of the tape fasteners has drawbacks that the tape fasteners inevitably have stiffness higher than that of any other components constituting the diaper, e.g., the top- and backsheets as well as the liquid-absorbent core and, in addition, the wearer may experience uncomfortable irritation should the wearer""s skin come in contact with the tape fasteners during use of the diaper. Furthermore, once the pressure-sensitive adhesive surface has been fouled, the tape fasteners will lose its initial bonding property and no more useful.
It is an object of this invention to provide a disposable pull-on diaper improved so that the diaper can be secured in rolled up state for disposal without use of the so-called tape fasteners.
According to this invention, there is provided a disposable pull-on diaper comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between these two sheets to constitute a front waist region, a rear waist region opposed to said front waist region and a crotch region positioned between these two waist regions wherein said front and rear waist regions are joined together along first joining zones extending in a longitudinal direction in the vicinity of transversely opposite side edges of said front and rear waist regions to define a waist-opening and a pair of leg-openings.
The pants-type disposable diaper further comprises a pair of slits being defined between the transversely opposite side edges and said first joining zones, by tearing said topsheet and said backsheet, the slits extending in said longitudinal direction between the vicinity of a peripheral edge portion and the vicinity of peripheral edge portions of said leg-openings so that a pair of ribbon-like portions which extend in said longitudinal direction being formed between said slits and the transversely opposite side edges of said front and rear waist regions.
According to one preferred embodiment of this invention, perforated lines serving to tear said top- and backsheets are defined between the transversely opposite side edges of said front and rear waist regions and said first joining zones, respectively, and extend in said longitudinal direction between the vicinity of said peripheral edge portion of said waist-opening and the vicinity of said peripheral edge portions of said leg-openings so that said top- and backsheets may be torn along said perforated lines to define said slits.
According to another preferred embodiment of this invention, said ribbon-like portions are formed in second joining zones extending in said longitudinal direction.